The surface area of materials is a property of great significance in several applications. Silica-alumina and carbon black are two examples of products where one of the important characteristics is the surface area. In several catalytically promoted reactions, the surface area of the catalyst determines not only the yield of the process, but in several instances, the reactions result and the chemical composition of the product made.
In view of the importance of the surface area, methods have been developed for an accurate determination thereof. One known method consists in contacting a weighed sample, the surface area of which is to be determined, with fluid which is adsorbed onto the surface area of the sample. The larger the surface area of the samples of the same weight will be, the larger the quantity of adsorbed fluid on such a sample will be. The so pretreated sample is then subjected to heat to effect desorption of the adsorbed fluid into a carrier gas stream. The carrier gas stream containing the desorbed adsorbing fluid is passed through a detector from which the amount of adsorbing fluid that has been desorbed from the samples in the carrier gas is measured, displayed, registered. Thereby the total quantity of desorbed adsorbing fluid can be determined and the surface area of the sample can be determined.
Whereas the process described is very accurate and effective, it is also a time consuming and labor intensive procedure. It would be desirable to have an apparatus and method available which allow the measurement of a multitude of samples and which lend themselves to automatic operation.
Therefore, it is one object of this invention to provide an apparatus for measuring the amount of a fluid desorbed from a plurality of samples. Another object of this invention is to provide a process for measuring the quantity of an adsorbing fluid desorbed on each of a plurality of samples without having to complete each and every step of the measurment on one sample before the next sample can be handled, but still using only one detecting device.
A further object of this invention is to provide means for automatic measurement of the surface area of a plurality of samples.